1.1. Filling Fats and Cream Fats.
A first important application area of confectionery fats is the so-called filling and cream fats. Filling and cream fats are used for the production of for example soft centres for pralines or confectionery bars or for creams used in or on biscuits or wafers. To be suitable for use as a cream and/or filling fat, it is important that the fat has specific properties such as good melting properties in the mouth, good creaminess as well as a stable crystal structure. Several types of fats capable of providing these properties are known in the art.
A first class of fats suitable for use as filling and/or cream fats includes the so-called lauric fats. The lauric fats are derived from coconut oil or palm kernel oil and contain a high amount of lauric and myristic acid. By subjecting these lauric fats to a fractionation and/or a hydrogenation reaction, a lauric fat with a steep SFC-profile can be obtained, i.e. a lauric fat of which the solid fat content (SFC) as a function of temperature is high at room temperature, whereas at body temperature the solid fat content is low and the fat is completely molten. This sharp transition from solid to liquid gives a cool sensation in the mouth. Besides showing a steep SFC-profile, lauric fats show a quick solidification, which is an advantage when used in fillings and creams. Although they are frequently applied in practise, lauric type fats have a number of disadvantages, a major disadvantage being the risk to saponification of the lauric acid upon ageing, involving the occurrence of a bad taste. Another disadvantage of lauric fats is their high saturated fatty acid content, often over 80%, which is considered an important nutritional disadvantage.
A second class of cool melting filling and cream fats is based on fractionated palm oil. Palm oil as such shows a rather flat SFC-curve with a SFC at 20° C. of only 25%, while at 35° C. the SFC is 6%. By subjecting palm oil to a fractionation process a product with steep SFC-profile can be obtained. Fractionation of palm oil is carried out by cooling palm oil to a certain temperature, until a liquid phase containing triglycerides with a the lower melting point and a solid phase containing triglycerides with a higher melting point, is obtained. Reduction of the tailing effect of the SFC curve is achieved by removing the high melting part, which mainly consists of trisaturated triglycerides like tripalmitine. Fats associated with this tailing cause a waxy feeling in the mouth upon eating. In a next stage, through removal of the part with the lower melting temperature, which mainly comprises tri- or di-unsaturated triglycerides like tri-oleine or 1-palmitic 2-3-oleic triglycerides, the SFC at room temperature is increased. The fraction remaining after removal of the higher and lower melting part of the palm oil is commonly indicated by the name PMF (palm mid fraction).
The most important advantages of PMF-based filling and cream fats are their non-lauric nature, the lower content of saturated fatty acids, the fresh melting sensation upon eating and the fact that PMF is a non-hydrogenated fat. A major disadvantage of PMF however resides in the rather long and laborious fractionation process involved, together with the rather low production yields, which renders the product expensive: starting from palm oil only 25-30% of PMF is obtained. The yields of hard PMF obtained via double fractionation are even lower. A further disadvantage is the slow solidification rate of PMF, which necessitates in the confectionery plant the use of devices with high cooling capacities. Besides this, PMF based fats show a risk to re-crystallisation, causing “graininess” of the final product when stored for some time, in particular in case no tempering is applied.
A third type of filling and cream fats is based on hydrogenated liquid oils or hydrogenated olein fractions. This type of fat compositions is characterised by a good creaminess and good melting properties, although they may show less cooling sensation in the mouth, which is typical for the two previous types of fat compositions. Products containing these fats show a quick solidification and a stable texture. In addition to this, hydrogenated liquid oils and olein fractions are less expensive compared to the former products since their raw materials are largely available and their processing is less complicated as compared to palm oil fractionation. The presence of trans fatty acids entails the advantage of improving the crystallisation rate. The big disadvantage of hydrogenated liquid oils and olein fractions however is their too high content of trans fatty acids (TFA), which is a health concern of increasing importance. In fact, trans fatty acids are unsaturated fatty acids. However, they have undesirable effects comparable to or even worse than saturated fatty acids (SFA). This is why there is an interest to not only control the SFA level of a fat composition, but to control also the sum of the TFA and SFA levels. To get products with steep SFC-profiles, the hydrogenation reaction is mostly carried out in the presence of a trans-specific catalyst, for example S-poisoned Ni-catalysts.
From the above, it will become clear that there is a need to a fat composition suitable for use as a confectionery fat or baking fat and to a method for producing such a fat composition. There is a need to a fat composition which preferably is non-lauric, which is characterised by a good melting in the mouth without involving waxiness, which shows a sufficiently high crystallisation rate and has an interesting nutritional profile, which means that the composition should have a low content of both saturated and trans fatty acids. Furthermore it is of interest that the fat composition may be produced at an acceptable cost.
From EP-A-547.651 it is known to use a blend of (i) a non lauric fat, in particular a mid-fraction obtained from wet fractionation of hardened soybean oil containing fat mixtures; and (ii) a liquid, trans-hardened high stability oil, in particular olein fractions obtainable from wet fractionation of hardened soybean oil containing fat mixtures. Thereto, combinations of soybeanoil and palm oil olein are subjected to a trans-selective hydrogenation reaction. In the wet fractionation preferably aceton is used as a solvent, for the trans-selective hydrogenation a sulphided Ni-catalyst is found very suitable. The blends of mid-fractions and olein-fractions of such trans-hydrogenated combinations give filling fats with a minimised waxiness, a steep melting curve and, a steep SFC-profile with N20>40% and N30<8%, and good mouthfeel. However, the trans fatty acid content of these fat composition ranges from 35 to 45%, which is too high.
1.2. Coating Fats and Hard Centre Fats.
Besides the above discussed application of confectionery fats in fillings and creams, there is a second important application area for confectionery fats of a harder type in hard centres and in confectionery coatings and tablets. These include the so called hard butters. Hard centres is understood to designate confectionery centres with a firm texture, that are usually produced by extrusion. Hard butters are characterised by a steep SFC-profile: they have a high solid fat content and are hard at room temperature. At body temperature they melt and their solid fat content becomes negligible. The SFC profile of these confectionery fats is similar to that of cocoa butter, which is the traditional chocolate fat.
Over the years, three main classes of hard butters have been developed for use in coatings or tablets including (i) lauric cocoa butter substitutes, (ii) cocoa butter equivalents (CBE) containing palm oil fractions combined with so-called wild fats like illipe or shea fat, and (iii) non-lauric cocoa butter replacers (NL-CBR) based on trans-specific hydrogenated liquid oils or liquid fractions. These three classes of cocoa butter alternatives correspond to the three classes of filling fats described above.
In general, fillings and creams will be softer than tablets and coatings. The reasons for the higher softness of fillings and creams resides in the higher fat content of these products as compared to tablets and coatings and in the softer nature of the fats contained therein i.e. the lower SFC at room temperature. Both for filling and cream fats and for coating fats it is important to have a steep SFC-profile, which means that at room temperature the SFC should be sufficiently high, whereas at body temperature the SFC should be low, in order to avoid a “waxy” mouthfeel. This explains the similar approach used in the production of filling/cream fats and the so-called hard butters.
Palm fractions used for CBE are typically obtained by wet fractionation, which gives a PMF of better quality as compared to PMF obtained from dry or detergent fractionation, the wet fractionation process however being the more expensive one. In the wet fractionation process use is made of acetone, hexane or any other suitable solvent. The wet fractionation process guarantees a sharp fractionation, with an efficient removal of low melting triglycerides like POO (P=Palmitic acid; O=Oleic acid) and high melting triglycerides like PPP. The wet fractionation is also an efficient process for removing diglycerides from the palm mid fraction, which are to be avoided in CBE products. It is important to mention here that CBEs differ from non-lauric CBR and lauric cocoa butter substitutes in that they are a tempering type of fat, similar to natural cocoa butter. Tempering is a process step in which a molten chocolate mixture is subjected to a temperature conditioning process, in particular the molten chocolate mixture is subjected to a process involving cooling and heating, with the aim of stimulating and maximising crystallisation of the fat in a stable crystalline form.
The production of non-lauric CBR is described by W. Soon in “Specialty fats versus Cocoa Butter” page 189-192. According to W. Soon, liquid oils like soybean oil, rapeseed oil and sunflower oil are suitable raw materials for a hydrogenation process, as well as liquid fractions like highly fractionated palm olein (iodine value >68). However, according to W. Soon, care needs to be taken to carry out the hydrogenation process in such a way as to minimise the production of trisaturated triglycerides (SSS where S=Saturated), as these have a high melting point and induce waxiness. This may be achieved by appropriate selection of the catalyst. Instead of using a conventional catalyst, W. Soon advises to carry out the hydrogenation reaction in the presence of a sulphur poisoned nickel catalyst as this promotes the formation of trans-isomers, which give a steep SFC-profile, formation of SSS isomers being minimised. To produce non-lauric CBR based on palm oil, it is advisable to use as a starting material a palm olein the PPP and PPO/POP content of which is as low as possible. PPP is a trisaturated fatty acid that is naturally present in palm oil. With PPO and POP saturation of one single fatty acid suffices to build trisaturated fatty acids.
The effect of using a sulphur poisoned Ni-catalyst in a hydrogenation reaction of palm olein in stead of a traditional non trans specific Ni-catalyst on palm olein has been described by H. Mori in “Crystallisation and polymorphism of fats and fatty acids” pg 430-431. According to Mori when using a trans specific catalyst, a confectionary fat with a sharp melting curve is obtained, which is not the case when using conventional hydrogenation catalyst.
U.S. Pat. No. 4,205,095 relates to a method for the production of cocoa butter substitutes, according to which a palm mid fraction is subjected to a catalytic hydrogenation reaction in the presence of a nickel, platinum or palladium catalyst. The purpose of the hydrogenation reaction is to extend the possibilities of blending PMF with cacao butter by removing triglycerides containing more than one unsaturated fatty acid (SU2 and U3) as much as possible and by converting polyunsaturated hydrocarbon chains of the fatty acids into mono-unsaturated hydrocarbon chains, thereby reducing the iodine value to 38-45, the linoleic acid content to below 2% and achieving a fat composition with a melting point of between 33-36° C. The cocoa butter substitutes disclosed in U.S. Pat. No. 4,205,095 are meant to be used in chocolate products like tablets or coatings.
From U.S. Pat. No. 3,686,240 a process is known for producing a vegetable fat product which is suitable for replacing at least part of cocoa butter in chocolate, the properties of the vegetable fat product being similar to those of cocoa butter. According U.S. Pat. No. 3,686,240 this vegetable fat product is obtained by subjecting a palm oil middle melting point fraction (PMF) to a hardening process through hydrogenation of the fraction. The fractionation and hydrogenation process are carried out so as to become a fat which upon blending with natural cocoa butter should not soften or get a lower melting point and thus shows full compatibility with cocoa butter. The full compatibility with cocoa butter implies that the product obtained with this process is a tempering type of fat. It is further explained that the palm mid fraction should be prepared by solvent fractionation using a specific solvent.
1.3. Caramel.
A third kind of application of fats in the confectionery area is their use in caramel. Caramel is understood to include both high boiling and soft caramels. Fats give a certain consistency to the caramel, they control chewiness and reduce stickiness. In caramels, traditionally hydrogenated liquid oils such as hydrogenated soybean oil or hydrogenated rapeseedoil are used. Lauric fats like hydrogenated palmkernel or hydrogenated coconutoil can also be used. Because of the too high content of trans fatty acids or saturated fatty acids, there is a need for alternatives having a low trans fatty acid content, showing at the same time a similar melting profile and which may be produced at an acceptable cost for this application as well.
1.4. Margarine and Bakery Products.
Next to the application of fats in confectionery, there is an important use of fats in the preparation of baked goods. Fats employed in bakery dough production may contain high amounts of trans fatty acids, as they are often obtained by partial hydrogenation of liquid oils like soybeanoil, rapeseed oil, sunflowerseedoil, etc. These oils are popular, as they are available in large quantities at attractive prices, and through hydrogenation of the oils a whole range of fats can be produced with different SFC-profiles depending on the texture of the dough one wants to obtain. Hydrogenation not only gives plasticity to the product, but it also increases the stability of the oil. The problem with these liquid oils is however that in the course of the hydrogenation, the high amounts of unsaturated fatty acids present in the raw material, easily isomerise to trans fatty acids. Although these fatty acids provide additional functionality to the fat composition, for example increased crystallisation speed, they are unwanted because of their adverse health effect.
Fats are employed in baking applications as a shortening or as margarine. A shortening can be defined as a functional plastic solid fat prepared by carefully cooling, plasticizing and tempering a blend of molten fats and oils. Margarines relate to a water-in-oil emulsion. Margarines and shortenings have an important functionality in baking: they contribute to the quality of the finished product by imparting a creamy texture and rich flavour, tenderness and uniform aeration for moisture retention and size expansion.